Ok, here are my answers:
(1) Yes, something like this should do it:
Rule Type: order
Minimum Order Total Type: Per order
Order Number to trigger rule: 10
Credit type: points
(2) For this no, there is nothing that would automatically apply the generated code and disable being sent by email. But you can use AwoCoupon Balance, since you have AwoCoupon pro installed. I know you said no points, but it might make sense here. You setup the rule as in (1). Then in AwoRewards config, go to Automatic Payout.
Payment Type: AwoCoupon Balance
Points to Amount Ratio: 1
Minimum payout: 0.01
Then when a customer gets rewarded for their 10th order with 10 points, the points are automatically converted to store credit of $10 in the customer's account. And as long as you have setup a module in checkout to use their store credit, it is simply 1 click to use:
(3) No. System coupons are there for those that do not have AwoCoupon Pro installed.
(4) Yes correct, a new unique code is always generated.
(5) It depends on the type of coupon. If the coupon is a gift certificate, then no, because gift certificates do not attach to any specific customer. But every other type of coupon would. And if you are setting number of uses to 1 then you are not using a gift certificate, so yes, in that situation, the code generated would be specific to the customer who it was generated for. No one else can use it.